As is well known, in molding machines such as an injection molding machine, there is a molding machine having a configuration in which a mold clamping force during molding (for example, injection molding) generated between a fixed platen on which a fixed mold is disposed and a movable platen on which a movable mold is disposed is retained by a tensile force of a tie bar.
In the molding machine having such a configuration, a mold clamping device having a configuration in which when the movable platen and the fixed platen are in a mold clamping state, a locking-shaped portion formed in the tie bar is gripped by a half nut or the like, thereby making the movable platen be retained on the fixed platen, is widely known (refer to, for example, PTL 1).
Further, in the molding machine having such a configuration, there is also a method of performing mold opening (hereinafter, referred to as mold release) by moving the tie bar in a direction in which the movable platen is opened, by driving the movable platen through the half nut by the tie bar in a state where the locking-shaped portion formed in the tie bar remains gripped by the half nut or the like, because a large mold opening force is required at the time of a mold opening operation to separate the fixed mold and the movable mold from a mold clamping state when extracting a molded article after resin is filled into a mold.
In this manner, in the mold clamping device to grip the tie bar by the half nut or the like, for example, as shown in FIG. 14, a connection mechanism 123 is used in which a flange 124 provided at a half nut 121 is pressed by a knuckle 125 of a tip portion of a rod 122 of an actuator (for example, a hydraulic cylinder), thereby fixing the actuator to the half nut. In this case, in order to fix the rod 122 to the half nut 121 without rattle, usually, connection is performed by the knuckle 125 and the flange 124 with a clearance 126 provided.